Various adhesives can individually be advantageously used as pressure sensitive, laminate or hot melt adhesives. Most are generally known for their ability to form articles by bonding laminates together. Some are more particularly known as pressure sensitive adhesives and some as hot melt adhesives.
Pressure sensitive adhesives and adhesive-coated masking tapes and the like are well known. These products commonly contain a mixture of natural rubber or styrene/isoprene/styrene block polymer and a thermoplastic tackifier resin compatible therewith. The adhesive, coated on a flexible backing to form a tape, is tacky at normal room temperatures and adheres instantly and tightly to surfaces against which it is pressed without requiring moistening or heating. It typically is required to have a balance of good shear strength, a satisfactory 180.degree. peel strength, and good tack property in order to be commercially useful.
Adhesives are many times based on mixtures of rubbery materials and tackifiers. Pressure-sensitive adhesives typically require more sophisticated properties than simple tackified rubber compositions. They must have especially balanced properties of adhesion, cohesion and elasticity in addition to peel and shear strengths to be useful for adhering materials together on a pressure-sensitive basis.
Many times, pressure-sensitive adhesives can be based on mixtures of tackifiers with natural rubber or with block copolymers of isoprene and styrene. However, such adhesive composites are often deficient in desirable properties.
It is, therefore, an object of this invention to provide an adhesive composition of a tackifier and a rubbery block polymer product of styrene and isoprene.